562 PHILOSOPHICAL TRANSACTIONS. [aNNO 1682-3. 



these orifices in the head; and Charas says that they hear by the nostrils ; and 

 that to them run not only the olfactory but auditory nerves also. The eye was 

 round, about ^ of an inch diameter ; in colour, the make of the pupil, and 

 other respects, like a viper's, as indeed, except in the rattle, was the whole ex- 

 ternal shape of this animal. There was a large scale jetting over the eye, which 

 seemed to serve as a palpebra for defending it from any thing falling on it ; but 

 I could not perceive it was capable of closing, although inwards it seemed to 

 have a membrana nictitans, which removes any dust that might adhere to 

 the eye. 



The scales on the head were the smallest of any ; those on the back larger, 

 and so proportionably greater to the largest part of the body; and so diminish- 

 ing thence again to the setting on of the rattle; all in figure somewhat resem- 

 bling parsnip seeds. Their colour various : the scales on the back had an edged 

 rising in the middle, which was still less protuberant as they grew nearer the 

 sides, where they were flat. 



The belly seemed flat, covered with long scales of a yellowish colour, speckled 

 black. From the neck to the anus we numbered 168; beyond the anus were 

 two half scales ; thence 1 9 whole scales of a black lead colour with yellowish 

 edges; from thence to the rattle 6 orders or rows of smaller scales of the same 

 colour. 



The scales of the belly were joined to each other by distinct muscles; the 

 lower tendon of each muscle being inserted into the upper edge of the following 

 scale ; and the other tendon of the same muscle inserted about the middle of 

 the foregoing scale. These muscles (fig. 1, s,s,s) were more fleshy towards 

 the middle of the scale; and then its fibres ran obliquely ascending. To each 

 scale was appropriated a rib, whose point joined with the extreme of it, which 

 must much advantage the use nature seems to design them for, by strengthen- 

 ing them to perform their reptile motions ; for the scales are as so many feet^ 

 which being free and open downwards, they thereby take hold of the ground, 

 and so contract their body forwards, and then shoot out again, and so perform 

 their motion. Whence it is observed by Nierembergius,* that on rocks their 

 motion is much quicker than on the earth or plains. 



Since they must be always grovelling on the ground, it is a provision of na- 

 ture in furnishing them with this coat of armour for their defence ; which is so 

 curiously contrived, that though it covers the whole, yet by its frequent joint- 

 ings it admits of all motions. And for this too, the vertebras of the spine seem 

 admirably contrived ; there being a round ball in the lower part of the upper 



* Hist, exotic. 1. 12, c. 1.— Orig. 



